Basically this guy kinda likes this girl. Its a bit like unrequited love. Then all of a sudden, a lot of girls try to rape him and stuff. A guy from the future stops him from having intercourse with them, and tells him if he has sex with any woman other than the one he likes, there will be mass destruction. He also threatens to kill him, but its not that serious.

I read it around a year ago (yep, pretty long ago...) and it seems to be ongoing. 10-20 chapters? I guess extra genres include Shonen/Seinen and School life. Possible Ecchi.
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user4881May 14 '14 at 2:15

1 Answer
1

This sounds like Tadashii Kodomo no Tsukurikata!. The synopsis from MAL is kind of misleading, as that's not really the main premise. There's a review on that page that describes it better:

First of all, after reading synopsis one would think that the guy traveling back to the past to change the future would be the protagonist, right? Well not a chance, he's only a side character, telling the "real" protagonist what to do, as if that weren't misleading enough his goal is rather ridiculous from the beginning. So let me get this clear - if the protagonist has children with any of the girls, that'll cause the appearance of the horrible virus which will destroy humanity, but there's one girl, childhood friend, who wouldn't cause this, so the guy from the future came to make sure the protagonist will have children with her